1. Field of the Invention
The present invention relates to a vehicle suspension, and more particularly to an interconnected suspension for a vehicle, having interconnected control arms on both sides.
2. Description of the Related Art
A suspension that links a wheel axle to a vehicle body is a device for preventing the vehicle body from being damaged and for securing the ride and stability of the vehicle, by absorbing vibration or shock the axle receives from a road surface. The suspension is composed of a chassis spring for relieving shock, a shock absorber for elevating the vehicle ride by controlling free vibrations of the chassis spring, and a stabilizer bar for preventing the rolling of the vehicle body. Depending on which part of vehicle body the suspension is mounted, the suspension is divided into a front suspension and a rear suspension. Also, there is a rigid axle suspension in which the wheels on both sides are linked by one single axle, and an independent suspension with an excellent road-holding and handling, which can be applied to each of the wheels, respectively.
Particularly, a multi-link type suspension, one of rear suspensions, is disclosed in Korean Patent Registration No. 10-0192402. According to this patent, the rear suspension apparatus comprises on both ends of a cross member a front lower arm, a center lower arm and a rear lower arm, each being rotatable in a vertical direction, a knuckle having a tire (wheel) holding portion for helping the rotations of the front lower arm, the center lower arm and the rear lower arm, a shock absorber mounted on a lower end portion of the knuckle in an upward direction, and an upper arm linked to the top end portion of the knuckle by a ball joint as well as to the vehicle body.
U.S. Pat. No. 6,179,328 to Nissan Motor Co., on Jan. 30, 2001 describes the rear suspension. According to this invention, the rear suspension apparatus is comprised of a vehicle superstructure, an axle including a pair of trailing arms having wheel supports, an interconnecting assembly for connecting the axle with the vehicle superstructure, and a linkage mechanism operatively connected between the vehicle superstructure and the beam, wherein the linkage mechanism includes a resilient bushing, and each of concentric inner and outer rigid elements of the resilient bushing are connected to the link, the bracket, and an elastic body between the inner and outer elements.
U.S. Pat. No. 5,505,479 to Hyundai Motor Co., on Apr. 9, 1996 discloses an anti-roll system of a vehicle suspension.
FIG. 1 is a perspective view of the anti-roll system for a vehicle suspension in accordance with the related art.
As depicted in FIG. 1, the anti-roll system does not cause geometrical interference with the existing suspension system, since there are hinge portions 12a and 12b at a mid-point, the hinge portions being capable of easily changing the anti-roll efficiency, depending on the strength of the roll. Further, the anti-roll system comprises a pair of lower control arms 11a and 11b including horizontal portions 13a and 13b and vertical portions 14a and 14b being combined with each other as one body, each control arm being pivotally connected to a subframe 1, a pair of connecting arms 15a and 15b disposed in a horizontal direction on a vehicle body, each of connecting arms having one outer end pivotally connected to the front vertical portions 14a and 14b of the lower control arms 11a and 11b, respectively, and an elastic member 16 fixed to a mount 17 whose mid-point is rotatably disposed on the subframe 1, thereby being able to turn left and right (horizontally) when viewed from the top, wherein a front end portion and a rear end portion of the elastic member is connected to the connecting arms 15a and 15b. 
However, the anti-roll system discussed above has the defects as follows.
Suppose that a vehicle is running on a very rough and uneven road surface. If a wheel on one side bumps against the uneven road surface under the influence of the stiffness of the chassis spring, another wheel on the other side correspondingly bumps too, and as a result, the ride is reduced. Therefore, there is a need to increase the damping force in order to make the wheels not lose contact with that rough road surface.